Folding sofa



FIG. 1 is a front elevational view of a folding sofa showing my new design;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a first perspective view thereof;

FIG. 8 is a second perspective view thereof; and,

FIG. 9 is a third perspective view of the device arranged as a bed.

The broken lines in the drawings illustrate portions of the folding sofa which form no part of the claimed design. 

CLAIM The ornamental design for a folding sofa, as shown and described. 